Ok, so the only difference between those two is the type of plastic they're made of. Based on the stamping on the factory one, it's PBT so I'll match that with the male end. That means 7282-6458-40 is the correct part.
After some searching around, I found it for sale on Ebay for $14, plus $5 shipping. So $20. Expensive little connector, but I love the fact this enables me to do this really clean.
(Alternative was buying a minimum of 10 of them from a bulk distributor for $50.)
So next steps for myself regarding the gray connector:
- Figure out the pins. The Yazaki site lists the part number for them, so I just need to find them, or an equivalent, for purchase.
- Figure out amperages to be sure I'm happy with the safety of things.
- Order parts!
Next steps for the brown connector:
- Do a touch more research to see if I can find a male portion that's intended to go to a wire, rather than be soldered to a board.
- Order the one I can and figure out adapting it to a wire.
Then it's do the conversion!